Systems Operation Introduction NOTE: For Specifications with illustrations, make reference to Specifications for 3306B Generator Set Engine, SENR1092. If the Specifications in SENR1092 are not the same as the Systems Operation and the Testing & Adjusting, look at the printing date on the front cover of each book. Use the Specifications given in the book with the latest date.
Engine Design
Cylinder And Valve Identification
Bore ... 120.7 mm (4.75 in) Stroke ... 152.4 mm (6.00 in) Number of Cylinders ... 6 Cylinder Arrangement ... in-line Firing Order (Injection Sequence) ... 1,5,3,6,2,4 Direction of Rotation (when seen from flywheel end) ... Counterclockwise The No. 1 Cylinder Is Opposite Flywheel End.
Fuel System Fuel Flow
Fuel System Schematic (1) Fuel tank. (2) Fuel return line. (3) Priming pump. (4) Fuel injection nozzle. (5) Fuel injection line. (6) Fuel injection pump. (7) Primary fuel filter. ( 8) Check valve. (9) Fuel transfer pump. (10) Secondary fuel filter. (11) Constant bleed orifice. (12) Fuel injection pump housing.
Fuel is pulled from fuel tank (1) through primary fuel filter (7) and check valves (8) by fuel transfer pump (9). From the fuel transfer pump the fuel is pushed through secondary fuel filter (10) and to the fuel manifold in fuel injection pump housing (12). The pumping spring in the fuel transfer pump keeps the fuel pressure in the system at 170 to 290 kPa (25 to 42 psi). Constant bleed orifice (11) lets a constant flow of fuel go through fuel return line (2) back to fuel tank (1). This helps keep the fuel cool and free of air. Fuel injection pump (6) gets fuel from the fuel manifold and pushes fuel at very high pressure through fuel injection line (5) to fuel injection nozzle (4). The fuel injection nozzle has very small holes in the tip that change the flow of fuel to a very fine spray that gives good fuel combustion in the cylinder.
Fuel Injection Pump The fuel injection pump increases the pressure of the fuel and sends an exact amount of fuel to the fuel injection nozzle. There is one fuel injection pump for each cylinder in the engine. The fuel injection pump is moved by cam (12) of the fuel pump camshaft. When the camshaft turns, the cam raises lifter (11) and pump plunger (7) to the top of the stroke. The pump plunger always makes a full stroke. As the camshaft turns farther, spring (8) returns the pump plunger and lifter to the bottom of the stroke. When the pump plunger is at the bottom of the stroke, fuel transfer pump pressure goes into inlet passage (1), around the pump barrel and to bypass closed port (3). Fuel fills the area above the pump plunger. After the pump plunger begins the up stroke, fuel will be pushed out the bypass closed port until the top of t he pump plunger closes the th e port. As the pump plunger travels farther up, the pressure of the fuel increases. At approximately 690 kPa (100 psi), check valve (2) opens and lets fuel flow into the fuel injection line to the fuel injection nozzle. When the pump plunger travels farther up, scroll (5) uncovers spill port (4). The fuel above the pump plunger goes through slot (6), along the edge of scroll (5) and out spill port (4) back to the fuel manifold. This is the end of the injection i njection stroke. The pump plunger can have more travel tr avel up, but no more fuel will be sent to the fuel injection injecti on nozzle.
Fuel Injection Pump (Typical Example) (1) Inlet passage. (2) Check valve. (3) Bypass closed port. (4) Spill port. (5) Scroll. (6) Slot. (7) Pump plunger. (8) Spring. (9) Fuel rack. (10) Gear. (11) Lifter. (12) Cam.
When the pump plunger travels down and uncovers bypass closed port (3), fuel begins to fill the area above the pump plunger again, and the pump is ready to begin another stroke. The amount of fuel the injection pump sends to the injection nozzle is changed by the rotation of the pump plunger. Gear (10) is attached to the pump plunger and is in mesh with fuel rack (9). The governor moves the fuel rack according to the fuel needs of the engine. When the governor moves the fuel rack, and the fuel rack turns the pump plunger, scroll (5) changes the distance the pump plunger pushes fuel between bypass closed port (3) and spill port (4) opening. The longer the distance from the top of the pump plunger to the point where scroll (5) uncovers spill port (4), the more fuel will be injected.
To stop the engine, the pump plunger is rotated so that slot (6) on the pump plunger is in line with spill port (4). The fuel will now go out the spill port and not to the injection nozzle.
Fuel Injection Nozzle The fuel injection nozzle goes through the cylinder head into the combustion chamber. The fuel injection pump sends fuel with high pressure to the fuel injection nozzle where the fuel is made into a fine spray for good combustion.
Fuel Injection Nozzle (Typical Example) (1) Carbon dam. (2) Seal. (3) Passage. (4) Filter screen. (5) Orifice. (6) Valve. (7) Diameter. (8) Spring.
Seal (2) goes against the cylinder head and prevents leakage of compression from the cylinder. Carbon dam (1) keeps carbon out of the bore in the cylinder head for the nozzle. Fuel with high pressure from the fuel injection pump goes into the inlet passage. Fuel then goes through filter screen (4) and into passage (3) to the area below diameter (7) of valve (6). When the pressure of the fuel that pushes against diameter (7) becomes greater than the force of spring (8), valve (6) lifts up. This occurs when the fuel pressure goes above the Valve Opening Pressure of the fuel injection nozzle. When valve (6) lifts, the tip of the valve comes off the nozzle seat and the fuel will go through orifices (5) into the combustion chamber. The injection of fuel continues until the pressure of fuel against diameter (7) becomes less than the force of spring (8). With less pressure against diameter (7), spring (8) pushes valve (6) against the nozzle seat and stops the flow of fuel to the combustion chamber.
The fuel injection nozzle can not be disassembled and no adjustments can be made.
Fuel Transfer Pump The fuel transfer pump is a piston pump that is moved by a cam (eccentric) on the camshaft for the fuel injection pump. The transfer pump is located on the bottom side of the fuel injection pump housing.
Fuel Transfer Pump (Start Of Do wn Stroke) (Typical Example) (Arrows Indicate Fuel Flow Direction) (1) Push rod. (2) Piston. (3) Outlet check valve. (4) Pumping check valve. (5) P umping spring. (6) Pump inlet port. (7) Inlet check valve. (8) Pump outlet port.
When the fuel injection pump camshaft turns, the cam moves push rod (1) and piston (2) down. As the piston moves down, inlet check valve (7) and outlet check valve (3) close. Pumping check valve (4) opens and allows the fuel below the piston to move into the area above the piston. Pumping spring (5) is compressed as the piston is pushed down by push rod (1).
As the fuel injection pump camshaft continues to turn, the cam no longer puts force on push rod (1). Pumping spring (5) now moves piston (2) up. This causes pumping check valve (4) to close. Inlet check valve (7) and outlet check valve (3) will open. As the piston moves up, the fuel in the area above the piston is pushed through the outlet check valve (3) and out pump outlet port (8). Fuel also moves through pump inlet port (6) and inlet check valve (7) to fill the area below piston (2). The pump is now ready to start a new cycle.
Fuel Transfer Pump (Start Of Up Stroke) (Typical Example) (Arrows Indicate Fuel Flow Direction) (1) Push rod. (2) Piston. (3) Outlet check valve. (4) Pumping check valve. (5) P umping spring. (6) Pump inlet port. (7) Inlet check valve. (8) Pump outlet port.
Oil Flow For Fuel Pump And Governor Oil from the side of the cylinder block goes to support (9) and into the bottom of front governor housing (4). The flow of oil now goes in three different directions. A part of the oil goes to the rear camshaft bearing in fuel pump housing (5). The bearing has a groove around the inside diameter. Oil goes through the groove and into the oil passage in the bearing surface (journal) of camshaft (7). A drilled passage through the
center of the camshaft gives oil to the front camshaft bearing and to the thrust face of the camshaft drive gear. Drain hole (6) in the front of fuel pump housing (5) keeps the level of the oil in the housing even with the center of the camshaft. The oil returns to the oil pan through the timing gear housing.
Fuel Pump And Governor (1) Cover. (2) Governor Servo. (3) Rear governor housing. (4) Front governor housing. (5) Fuel pump housing. (6) Drain hole. (7) Camshaft. (8) Drain hole. (9) Support.
Oil also goes from the bottom of the front governor housing through a passage to the fuel pump housing and to governor servo (2). The governor servo gives hydraulic assistance to move the fuel rack. The remainder of the oil goes through passages to the rear of rear governor housing (3), through cover (1) and back into another passage in the rear governor housing. Now the oil goes into the compartment for the governor controls. Drain hole (8) keeps the oil at the correct level. The oil in this compartment is used for lubrication of the governor control components and the oil is the supply for the dashpot. The internal parts of the governor are lubricated by oil leakage from the governor servo and the oil is thrown by parts in rotation. The flyweight carrier thrust bearing gets oil from the passage at the rear of the camshaft. Oil from the governor returns to the oil pan through a hole in the bottom of the front governor housing and through passages in the support and cylinder block.
Governor The governor controls the amount of fuel needed by the engine to maintain a desired rpm. The flyweights (7) are driven directly by the fuel pump camshaft. Riser (8) is moved by flyweights (7) and governor spring (1). Lever (6) connects the riser with sleeve (2) which is fastened to valve (3). Valve (3) is a part of governor servo (5) and moves piston (4).
Governor (1) Governor spring. (2) Sleeve. (3) Valve. (4) Piston. (5) Governor servo. (6) Lever. (7) Flyweights. (8) Riser. (9) Spring seat. (10) Stop bolt. (11) Load stop bar. (12) Power setting screw. (13) Stop collar.
The force of governor spring (1) always pushes to give more fuel to the engine. The centrifugal (rotating) force of flyweights (7) always push to get a reduction of fuel to the engine. When these two forces are in balance (equal), the engine runs at a constant rpm. When the governor control lever is moved to the high idle position, governor spring (1) is put in compression and pushes riser (8) toward the flyweights. When the riser moves forward, lever (6) moves sleeve (2) and valve (3) toward the rear. Valve (3) stops oil flow through governor servo (5) and the oil pressure moves piston (4) and the fuel rack
to the rear. This increases the amount of fuel to the engine. As engine speed increases, the flyweight force increases and moves the riser toward the governor spring. When the riser moves to the rear, lever (6) moves sleeve (2) and valve (3) forward. Valve (3) now directs oil pressure to the rear of piston (4) and moves the piston and fuel rack forward. This decreases the amount of fuel to the engine. When the flyweight force and the governor spring force become equal, the engine speed is constant and the engine runs at high idle rpm. High idle rpm is adjusted by the high idle adjustment screw. The adjustment screw limits the amount of compression of the governor spring. With the engine at high idle, when the load is increased, engine speed will decrease. Flyweights (7) move in and governor spring (1) pushes riser (8) forward and increases the amount of fuel to the engine. As the load is increased more, governor spring (1) pushes riser (8) farther forward. Spring seat (9) pulls on stop bolt (10). Stop collar (13) on the opposite end has power setting screw (12) that controls the maximum amount of fuel rack travel. The power setting screw moves forward and makes contact with load stop bar (11). This is the full load balance point.
Governor Servo The governor servo gives hydraulic assistance to the mechanical governor force to move the fuel rack. The governor servo has cylinder (3), cylinder sleeve (4), piston (2) and valve (1).
Governor Servo (Fuel On Position) (1) Valve. (2) Piston. (3) Cylinder. (4) Cylinder sleeve. (5) Fuel rack. (A) Oil inlet. (B) Oil outlet. (C) Oil passage. (D) Oil passage.
When the governor moves in the FUEL ON direction, valve (1) moves to the left. The valve opens oil outlet (B) and closes oil passage (D). Pressure oil from oil inlet (A) pushes piston (2) and fuel rack (5) to the left. Oil behind the piston goes through oil passage (C), along valve (1) and out oil outlet (B).
Governor Servo (Balanced Position) (1) Valve. (2) Piston. (3) Cylinder. (4) Cylinder sleeve. (5) Fuel rack. (A) Oil inlet. (B) Oil outlet. (C) Oil passage. (D) Oil passage.
When the governor spring and flyweight forces are balanced and the engine speed is constant, valve (1) stops moving. Pressure oil from oil inlet (A) pushes piston (2) until oil passages (C and D) are opened. Oil now flows through oil passage (D) along valve (1) and out through oil outlet (B). With no oil pressure on the piston, the piston and fuel rack (5) stop moving.
Governor Servo (Fuel Off Position) (1) Valve. (2) Piston. (3) Cylinder. (4) Cylinder sleeve. (5) Fuel rack. (A) Oil inlet. (B) Oil outlet. (C) Oil passage. (D) Oil passage.
When the governor moves in the FUEL OFF direction, valve (1) moves to the right. The valve closes oil outlet (B) and opens oil passage (D). Pressure oil from oil inlet (A) is now on both sides of piston (2). The area of the piston is greater on the left side than on the right side of the piston. The force of the oil is also greater on the left side of the piston and moves the piston and fuel rack (5) to the right.
Dashpot The dashpot helps give the governor better speed control when there are sudden speed and load changes. The dashpot has cylinder (1), piston (2), dashpot spring (3), needle valve (5) and check valve (6). Piston (2) and spring seat (4) are fastened to dashpot spring (3).
Dashpot (Governor Moving to Fuel On) (1) Cylinder. (2) Piston. ( 3) Dashpot spring. (4) Spring seat. (5) Needle valve. (6) Check valve. (7) Oil reservoir.
When the governor moves toward FUEL ON, spring seat (4) and piston (2) move to the right. This movement pulls oil from oil reservoir (7) through check valve (6) and into cylinder (1).
Dashpot (Governor Moving to Fuel Off) (1) Cylinder. (2) Piston. ( 3) Dashpot spring. (4) Spring seat. (5) Needle valve. (6) Check valve. (7) Oil reservoir.
When the governor moves toward FUEL OFF, spring seat (4) and piston (2) move to the left. This movement pushes oil out of cylinder (1), through needle valve (5) and into oil reservoir (7).
If the governor movement is slow, the oil gives no restriction to the movement of the piston and spring seat. If the governor movement is fast in the FUEL OFF direction, the needle valve gives a restriction to the oil and the piston and spring seat will move slowly.
Fuel Ratio Control
Fuel Ratio Control (Engine Stopp ed) (Typical Example) (1) Inlet air chamber. (2) Diaphragm assembly. (3 ) Internal valve. (4) Oil drain passage. (5 ) Oil inlet. (6) Stem. (7) Spring. (8) Piston. (9) Oil passage. (10) Oil chamber. (11) Lever.
Fuel Ratio Control (Increase In Inlet Air Pressure) (Typical Example) (1) Inlet air chamber. (2) Diaphragm assembly. (3) Internal valve. (4) Oil drain passage. (5) Oil inlet. (6) Stem. (7) Spring. (8) Piston. (9) Oil passage. (10) Oil chamber. ( 11) Lever.
Fuel Ratio Control (Ready for Operation) (Typical Example) (1) Inlet air chamber. (2) Diaphragm assembly. (3) Internal valve. (4) Oil drain passage. (5) Oil inlet. (6) Stem. (7) Spring. (8) Piston. (9) Oil passage. (10) Oil chamber. ( 11) Lever.
The fuel ratio control limits the amount of fuel to the cylinders during an increase of engine speed (acceleration) to reduce exhaust smoke. Stem (6) moves lever (11) which will restrict the movement of the fuel rack in the FUEL ON direction only. With the engine stopped, stem (6) is in the fully extended position. The movement of the fuel rack and lever (11) is not restricted by stem (6). This gives maximum fuel to the engine for easier starts. After the engine is started, engine oil flows through oil inlet (5) into oil chamber (10). From oil chamber (10) oil flows through oil passage (9) into internal valve (3) and out oil drain passages in stem (6). Stem (6) will not move until inlet manifold pressure increases enough to move internal valve (3). A line connects the inlet manifold with inlet air chamber (1) of the fuel ratio control. When inlet manifold pressure increases, it causes diaphragm assembly (2) to move towards the right. This also causes internal valve (3) to move to the right. When internal valve (3) moves to the right, it closes oil passage (9). When oil passage (9) is closed, oil pressure increases in oil chamber (10). Oil pressure moves piston (8) and stem (6) to the left and into the operating position. The fuel ratio control will remain in the operating position until the engine is shut off. When the governor control is moved to increase fuel to the engine, stem (6) limits the movement of lever (11) in the FUEL ON direction. The oil in oil chamber (10) acts as a restriction to the movement of stem (6) until inlet air pressure increases. As the inlet air pressure increases, diaphragm assembly (2) and internal valve (3) move to the right. The internal valve opens oil passage (9), and oil in oil chamber (10) goes to
oil drain passage (4). With the oil pressure reduced behind piston (8), spring (7) moves the piston and stem (6) to the right. Piston (8) and stem (6) will move until oil passage (9) is closed by internal valve (3). Lever (11) can now move to let the fuel rack go to the full fuel position. The fuel ratio control is designed to restrict the fuel until the air pressure in the inlet manifold is high enough for complete combustion. It prevents large amounts of exhaust smoke caused by an air-fuel mixture with too much fuel.
Air Inlet And Exhaust System Engines Without Turbocharger The air inlet and exhaust system components are: air cleaner, inlet manifold, cylinder head, valves and valve system components and exhaust manifold. When the engine is running, each time a piston moves through the inlet stroke, it pulls air into the cylinder. The air flow is through the air filter, inlet manifold, passages in the cylinder head and past the open inlet valve into the cylinder. Too much restriction in the inlet air system makes the efficiency of the engine less. When the engine is running, each time a piston moves through the exhaust stroke, it pushes hot exhaust gases from the cylinder. The exhaust gas flow is out of the cylinder between the open exhaust valve and the exhaust valve seat. Then it goes through passages in the cylinder head, through the exhaust pipe. Too much restriction in the exhaust system makes the efficiency of the engine less.
Engines With Turbocharger The air inlet and exhaust system components are: air cleaner, inlet manifold, cylinder head, valves and valve system components, exhaust manifold and turbocharger.
Air Inlet And Exhaust System (1) Exhaust manifold. (2) I nlet manifold. (3) Engine cylinders. (4) Air inlet. (5) Turbocharger compressor wheel. (6) Turbocharger turbine wheel. (7) Exhaust outlet.
Clean inlet air from the air cleaner is pulled through the air inlet (4) of the turbocharger by the turning compressor wheel (5). The compressor wheel causes a compression of the air. The air then goes to the inlet manifold (2) of the engine. When the inlet valves open, the air goes into the engine cylinder (3) and is mixed with the fuel for combustion. When the exhaust valves open, the exhaust gases go out of the engine cylinder and into the exhaust manifold (1). From the exhaust manifold, the exhaust gases go through the blades of the turbine wheel (6). This causes the turbocharger turbine wheel and the turbocharger compressor wheel to turn. The exhaust gases then go out the exhaust outlet (7) of the turbocharger.
Air Inlet And Exhaust System (Top Mounted Turbocharger) (1) Exhaust manifold. (2) Inlet manifold. (8) Turbocharger.
Air Inlet And Exhaust System (Rear Mounted Turbocharger) (1) Exhaust manifold. (2) Inlet manifold. (8) Turbocharger.
Engines With Turbocharger And Aftercooler (Rear Mounted Turbocharger)
Turbocharger And Aftercooler Installed (1) Air inlet. (2) Compressor wheel housing. (3) Exhaust outlet. (4) Air outlet. (5) Aftercooler housing. (6) Exhaust manifold. (7) Cylinder head. (8 ) Turbine housing. (9) Exhaust inlet.
Turbocharger (1) Air inlet. (2) Compressor wheel housing. (3) Exhaust outlet. (4) Air outlet. (5) Aftercooler housing. (6) Exhaust manifold. (7) Cylinder head. (8) Turbine housing. (9) Exhaust inlet. (10) Air filter. (11) Inlet air pipe for aftercooler.
Aftercooler (5) Aftercooler housing. (8) Turbine housing. (10) Air filter. (11) Inlet air pipe for aftercooler.
The air inlet and exhaust system components are: air cleaner, aftercooler, inlet manifold, cylinder head, valves and valve system components, exhaust manifold, and turbocharger. Clean inlet air from air filter (10) is pulled through air inlet (1) of the turbocharger by the turning compressor wheel. The compressor wheel causes a compression of the air. The air next goes through inlet air pipe (11) to aftercooler housing (5). The aftercooler cools the air. The air then goes to the inlet manifold which is part of cylinder head (7). When the inlet valves open, the air goes into the engine cylinder and is mixed with the fuel for combustion. When the exhaust valves open, the exhaust gases go out of the engine cylinder and into exhaust manifold (6). From the exhaust manifold, the exhaust gases go through the blades of the turbine wheel. This causes the turbine wheel and compressor wheel to turn. The exhaust gases then go out exhaust outlet (3) of the turbocharger.
Engines With Turbocharger And Aftercooler (Top Mounted Turbocharger)
Turbocharger And Aftercooler Installed (1) Aftercooler housing. (2) Exhaust outlet. (3) Turbine wheel housing. (4) Air outlet. (5) Compressor wheel housing. (6) Air inlet. (7) Cylinder head. (8) Exhaust manifold. (9) Exhaust i nlet. (10) Cylinder bore.
Turbocharger (1) Aftercooler housing. (2) Exhaust outlet. (3) Turbine wheel housing. (4) Air outlet. (5) Compressor wheel housing. (6) Air inlet. (8) Exhaust manifold. (9) Exhaust inlet.
Aftercooler (1) Aftercooler housing. (3) Turbine wheel housing. (4) Air oulet. (7) Cylinder head.
The air inlet and exhaust system components are: air cleaner, aftercooler (if so equipped), inlet manifold, cylinder head, valves and valve system components, exhaust manifold, and turbocharger. Clean inlet air from the air filter is pulled through the air inlet (6) of the turbocharger by the turning compressor wheel. The compressor wheel causes a compression of the air. On engines with an aftercooler, the air next goes to aftercooler housing (1). The aftercooler cools the air. The air then goes to the inlet manifold which is part of cylinder head (7). When the inlet valves open, the air goes into the engine cylinder and is mixed with the fuel for combustion. When the exhaust valves open, the exhaust gases go out of the engine cylinder and into exhaust manifold (8). From the exhaust manifold, the exhaust gases go through the blades of the turbine wheel. This causes the turbine wheel and compressor wheel to turn. The exhaust gases then go out exhaust outlet (2) of the turbocharger.
Aftercooler The aftercooler cools the air coming out of the turbocharger before it goes into the inlet manifold. The purpose of this is to make the air going into the combustion chambers more dense. The more dense the air is, the more fuel the engine can burn efficiently. This gives the engine more power.
Air To Air Aftercooler
Air Flow Schematic (Air To Air Aftercooler)
Inlet air is pulled through the air cleaner, compressed and heated by the compressor wheel in the compressor side of the turbocharger to about 148°C (298°F), then pushed through the air to air aftercooler core and moved to the air inlet manifold in the cylinder head at about 43°C (110°F). Cooling of the inlet air increases combustion efficiency, which helps to lower fuel consumption and increase horsepower output. The aftercooler core is a separate cooler core installed behind the standard radiator core. Air (ambient temperature) is moved across both cores by the engine fan. This cools the turbocharged inlet air and the engine coolant.
Turbocharger The turbocharger is installed on the exhaust manifold. All the exhaust gases from the engine go through the turbocharger. The exhaust gases enter the turbine housing (8) and go through the blades of turbine wheel (10), causing the turbine wheel and compressor wheel (4) to turn. When the compressor wheel turns, it pulls filtered air from the air cleaners through the compressor housing air inlet. The air is put in compression by action of the compressor wheel and is pushed to the inlet manifold of the engine. When engine load increases, more fuel is injected into the engine cylinders. The volume of exhaust gas increases which causes the turbocharger turbine wheel and compressor
wheel to turn faster. The increased rpm of the compressor wheel increases the quantity of inlet air. As the turbocharger provides additional inlet air, more fuel can be burned. This results in more horsepower from the engine.
Turbocharger (Typical Example) (1) Air inlet. (2) Compressor housing. (3) Nut. (4) Compressor wheel. (5) Thrust bearing. (6) Center housing. (7) Lubrication inlet passage. (8) T urbine housing. (9) Sleeve. (10) Turbine wheel. (11) Exhaust outlet. (12) Sleeve. (13) Oil deflector. (14) B earing. (15) Lubrication outlet passage. (16) Bearing. (17) Exhaust inlet.
Maximum rpm of the turbocharger is controlled by the rack setting, the high idle speed setting and the height above sea level at which the engine is operated.
NOTICE If the high idle rpm or the fuel setting is higher than given in the TMI (Technical Marketing Information) or Fuel Setting And Related Information Fiche (for the height above sea level at and which the engine is operated), there can be damage to engine or turbocharger parts. Damage will result when increased heat and/or friction, due to the higher engine output, goes beyond the engine cooling and lubrication systems abilities.
The bearings for the turbocharger use engine oil for lubrication. The oil comes in through the lubrication inlet passage (7) and goes through passages in the center section for lubrication of the bearings. Oil from the turbocharger goes out through the lubrication outlet passage (15) in the bottom of the center section and goes back to the engine lubrication system.
Cylinder Head And Valves There is one cylinder head for all cylinders. Each cylinder has one inlet and one exhaust valve. Each inlet and exhaust valve has a valve rotator. The valve rotator causes the valve to turn a small amount each time the valve opens and closes. This action helps keep carbon deposits off of the valve face and valve seat. The cylinder head has valve seats installed and they can be replaced. The valve guides can be replaced. There are threads on the inside diameter of the valve guides to hold oil that lubricates the valve stem.
Valve Mechanism The valve mechanism controls the flow of inlet air and exhaust gases in and out of the cylinders. The valve mechanism consists of rocker arms, push rods, valve lifters and camshaft. The camshaft is driven by and timed to the crankshaft. When the camshaft turns, the camshaft lobes move the valve lifters up and down. The valve lifters move the push rods which move the rocker arms. Movement of the rocker arms make the inlet and exhaust valves open according to the firing order (injection sequence) of the engine. A valve spring for each valve makes the valve go back to the closed position and holds it there.
Lubrication System System Oil Flow
Lubrication System Schematic (Engine Warm) (1) Oil passage (to front idler gear). (2) Oil passage (to turbocharger and fuel i njection pump). (3) Rocker arm shaft. (4) Oil pressure connection. (5) Oil manifold. (6) Piston cooling jets. ( 7) Camshaft bearing bore. (8) Engine oil cooler bypass valve. (9) Engine oil filter bypass valve. (10) Engine oil cooler. (11) Engine oil filter. (12) Turbocharger. (13) Engine oil pump. (14) Oil pan.
Engine oil pump (13) pulls oil from oil pan (14) and then pushes the oil to engine oil cooler (10). From the engine oil cooler the oil goes to engine oil filter (11) and then to oil manifold (5). From the oil manifold, oil goes to all main bearings, and piston cooling jets (6). Oil passages in the crankshaft send oil to the connecting rod bearings. Oil from the front main bearing goes through oil passage (1) to the bearing for the fuel injection pump idler gear. Oil from the front main bearing also goes to camshaft bearing bore (7).
The front camshaft bearing is the only bearing to get pressure lubrication. Oil passage (2) from No. 4 main bearing sends oil to turbocharger (12) and the fuel injection pump housing on the right side of the engine. An oil passage from the rear of the cylinder block goes below the head bolt hole and connects with a drilled passage that goes up next to the head bolt hole. A hollow dowel connects the vertical oil passage in the cylinder block to the oil passage in the head. The spacer plate has a hole with a counterbore on each side that the hollow dowel goes through. An O-ring is in each counterbore to prevent oil leakage around the hollow dowel. Oil flows through the hollow dowel into a vertical passage in the cylinder head to the rocker arm shaft bracket. The rocker arm shaft has an orifice to restrict the oil flow to the rocker arms. The rear rocker arm bracket also has an O-ring that seals against the head bolt. This seal prevents oil from going down around the head bolt and leaking past the head gasket or spacer plate gasket. The O-ring must be replaced each time the head bolt is removed from the rear rocker arm bracket. Holes in the rocker arm shafts let the oil give lubrication to the valve system components in the cylinder head. After the lubrication oil has done its work, it goes back to the oil pan. There is a bypass valve in the engine oil pump. This bypass valve controls the pressure of the oil coming from the engine oil pump. The engine oil pump can put more oil into the system than is needed. When there is more oil than needed, the oil pressure increases and the bypass valve will open. This allows the oil that is not needed to go back to the oil pan. With the engine cold (starting conditions), engine oil cooler bypass valve (8) and engine oil filter bypass valve (9) will open and give immediate lubrication to all components when cold oil with high viscosity causes a restriction to the oil flow through engine oil cooler (10) and engine oil filter (11). Engine oil pump (13) sends the cold oil through the bypass valves around the engine oil cooler and engine oil filter to oil manifold (5) in the cylinder block. When the oil gets warm, the pressure difference in the bypass valves decreases and the bypass valves close. Now there is a normal flow of oil through the engine oil cooler and engine oil filter.
Flow Of Oil (Engine Cold) (8) Engine oil cooler bypass. (9) Engine oil filter bypass. (10) Engine oil cooler. (11) Engine oil filter. (12) Turbocharger. (13) Oil pump. (14) Oil pan.
The bypass valves will also open when there is a restriction in the engine oil cooler or engine oil filter. This action does not let an engine oil cooler or engine oil filter with a restriction prevent lubrication of the engine.
Rocker Arm Oil Supply
Cooling System Radiator Cooling System (Engines Without Aftercooler)
Coolant Flow For Radiator Cooling System (Dry Manifold) (1) Radiator. (2) Pressure cap. (3 ) Inlet line to radiator. (4) W ater temperature regulator. (5) Cylinder head. (6) Cylinder block. (7) Inlet line to water pump. (8) Water pump. (9) Internal b ypass (shunt) line. (10) Engine oil filter. (11) Engine oil cooler. (12). Elbow. (13) Cylinder liner.
The water pump (8) is on the left front side of the engine. It is gear driven by the timing gears. Coolant from the bottom of the radiator (1) goes to the water pump inlet. The rotation of the impeller in the water pump (8) pushes the coolant through the system. All of the coolant flow from the water pump (8), in the standard system, goes through the engine oil cooler (11). The elbow (12) on the outlet side of the engine oil cooler (11) connects to the side of the cylinder block (6). On engines with an additional oil cooler (20) a bonnet (21) is mounted on the engine oil cooler (11). This bonnet (21) sends the coolant flow through the other cooler which is
for attachments, such as torque converters. The flow goes through one side on the way into the cooler. At the bottom of the cooler the flow turns and goes back up through the other side and into bonnet (21) again. Then bonnet (21) sends the coolant into the cylinder block (6).
Coolant Flow For Radiator Cooling System (Water Cooled Manifold) (1) Radiator. (2) Pressure cap. (3 ) Inlet line to radiator. (6) Cylinder block. (7) Inlet line to water pump. (8) Water pump. (9) Internal bypass (shunt) line. (11) Engine oil cooler. (14) Inlet line. (15) Manifold (water cooled or water cooled shield). (16) Outlet line. (17) Block. (18) Water cooled shield for turbocharger. (19) Return line. (20) Oil cooler (for torque converter or marine gear). (21) B onnet.
An engine can have a water cooled manifold or a water cooled shield for the manifold (15). If it has either one of these it can also have a water cooled shield for the turbocharger (18). The coolant flow from water pump (8) is divided. Some of the coolant goes through the standard system and some goes into the water cooled manifold or water cooled shield for the manifold (15) at the front of the engine. It comes out at the rear of the engine and goes through return line (19) to the bonnet (21) on the engine oil cooler (11). It mixes with the rest of the coolant from the standard system in the bonnet (21) and goes into the cylinder block (6). If the engine has a water cooled shield for the turbocharger (18), the supply of coolant for it comes from the bottom of the rear end of the water cooled manifold or water cooled shield for the manifold (15). The coolant goes through the water cooled shield
for the turbocharger (18). It goes out through outlet line (16) to block (17) at the top of the water cooled manifold or water cooled shield for the manifold (15). In the block (17) it mixes with the rest of the coolant on the way to the bonnet (21). Inside the cylinder block (6) the coolant goes around the cylinder liners (13) and up through the water directors into the cylinder head (5). The water directors send the flow of coolant around the valves and the passages for exhaust gases in the cylinder head (5). The coolant goes to the front of the cylinder head (5). Here water temperature regulator (4) controls the direction of the flow. If the coolant temperature is less than normal for engine operation, the water temperature regulator is closed. The only way for the coolant to get out of the cylinder head (5) is through the internal bypass (shunt) line (9). The coolant from this line goes into the water pump (8) which pushes it through the cooling system again. The coolant from the internal bypass (shunt) line (9).also works to prevent cavitation (air bubbles) in the coolant. When the coolant gets to the correct temperature, the water temperature regulator opens and coolant flow is divided. Some goes through the radiator (1) for cooling. The rest goes through the internal bypass (shunt) line (9) to the water pump (8). The proportion of the two flows is controlled by the water temperature regulator. NOTE: The water temperature regulator is an important part of the cooling system. It divides the coolant flow between radiator (1) and internal bypass (shunt) line (9), as necessary, to maintain the correct operating temperature. If the regulator is not installed, there is no mechanical control, and most of the coolant will take the path of least resistance through internal bypass (shunt) line (9). This will cause the engine to overheat in hot weather. In cold weather, even the small amount of coolant that goes through radiator (1) is too much, and the engine will not get up to normal operating temperature.
The internal bypass (shunt) line (9) has another function when the cooling system is being filled. It lets the coolant go into the cylinder head (5) and cylinder block (6) without going through the water pump (8). The radiator (1) has a pressure cap (2). This cap controls pressure in the cooling system.
Radiator Cooling System (Engines With Aftercooler)
Coolant Flow For Radiator Cooling System (Jacket Water Aftercooled - JWAC) (1) Radiator. (2) Pressure cap. (3 ) Inlet line for radiator. (4) Aftercooler. ( 5) Aftercooler inlet line. (6) Return line (from aftercooler). (7) Internal bypass (shunt) line. (8) Water pump. (9) Inlet line for water pump. (10) Engine oil cooler. (11) Bonnet.
Water pump (8) is on the left front side of the engine. It is gear driven by the timing gears. Coolant from the bottom of radiator (1) goes to the water pump inlet. The rotation of the impeller in water pump (8) pushes the coolant through the system. The coolant flow from the water pump (8) is divided. Some goes through engine oil cooler (10). Bonnet (11) on the outlet side of engine oil cooler (10) connects to the side of the cylinder block. On engines with an auxiliary oil cooler (14) a different bonnet (15) is on engine oil cooler (10). This bonnet (15) sends the coolant flow through auxiliary cooler which is for attachments, such as torque converters. The flow goes through one side on the way into the auxiliary oil cooler. At the bottom of the auxiliary oil cooler, the flow turns and goes back up through the other side and into bonnet (15) again. Then bonnet (15) sends the coolant into the cylinder block.
The remainder of the coolant flow goes through aftercooler inlet line (5) into the core of aftercooler (4). The core of aftercooler (4) is a group of plates and fins. The coolant goes through the plates. The inlet air for the engine goes around the fins. This cools the inlet air. The coolant comes out of the aftercooler (4) at the rear of the engine and goes through return line (6) to bonnet (11) on engine oil cooler (10). It mixes with the rest of the coolant from engine oil cooler (10) in bonnet (11) and goes into the cylinder block.
Coolant Flow For Radiator Cooling System (Jacket Water Aftercooled - JWAC) (1) Radiator. (2) Pressure cap. (3 ) Inlet line for radiator. (4) Aftercooler. ( 5) Aftercooler inlet line. (6) Return line from aftercooler. (7) I nternal bypass (shunt) line. (8) Water pump. (9) Inlet line for water pump. (10) Engine oil cooler. (12) Exhaust Manifold. (13) Turbocharger. (14) Auxiliary oil cooler. (15) Bonnet.
Inside the cylinder block, the coolant goes around the cylinder liners and up through the water directors into the cylinder head. The water directors send the flow of coolant around the valves and the passages for exhaust gases in the cylinder head. The coolant goes to the front of the cylinder head. Here the water temperature regulator controls the direction of the flow. If the coolant temperature is less than normal for engine operation, the water temperature regulator is closed. The only way for the coolant to get out of the cylinder head is through internal bypass (shunt) line (7). The coolant from this line goes into water pump (8) which pushes it through the cooling system again. The coolant from internal bypass (shunt) line (7) also works to prevent cavitation (air bubbles) in the coolant. When the coolant gets to the correct temperature, the water temperature regulator opens and coolant flow is divided. Some goes through radiator (1) for cooling. The rest goes through internal bypass (shunt) line (7) to water pump (8). The proportion of the two flows is controlled by the water temperature regulator.
NOTE: The water temperature regulator is an important part of the cooling system. It divides the coolant flow between radiator (1) and internal bypass (shunt) line (7), as necessary, to maintain the correct operating temperature. If the regulator is not installed, there is no mechanical control, and most of the coolant will take the path of least resistance through internal bypass (shunt) line (7). This will cause the engine to overheat in hot weather. In cold weather, even the small amount of coolant that goes through radiator (1) is too much, and the engine will not get up to normal operating temperature.
Internal bypass (shunt) line (7) has another function when the cooling system is being filled. It lets the coolant go into the cylinder head and cylinder block without going through water pump (8). Radiator (1) has a pressure cap (2). This cap controls pressure in the cooling system.
Heat Exchanger Cooling System (Jacket Water Aftercooled - JWAC)
Cooling System Schematic (1) Heat exchanger. (2) Expansion tank. (3) Pr essure cap. (4) Vent line. (5) Outlet line. (6) Outlet line. (7) Regulator housing. (8) Aftercooler inlet line. (9) Water cooled manifold. (10) Outlet line. (11) Water
cooled turbocharger. (12) Aftercooler housing. (13) Cylinder head. (14) Aftercooler outlet line. (15) Internal bypass (shunt) line. (16) T urbocharger inlet line. (17) Cylinder block. (18) Outlet line. (19) Bonnet. (20) Inlet line. (21) I nlet line. (22) Auxiliary pump. (23) Auxiliary pump. (24) Engine oil cooler. (25) Auxiliary oil cooler. (26) Outlet for external coolant sour ce. (27) Bypass valve. (28) Bypass li ne. (29) Duplex strainer. (30) Inlet (external coolant source).
This cooling system has two circuits which work together. The engine coolant (jacket water) circuit cools the aftercooler, the engine and the auxiliary oil cooler. The coolant from this circuit can go through expansion tank (2). In expansion tank (2) this coolant goes around the tubes of heat exchanger (1) while the coolant from the external coolant source goes through the tubes. In this way the external coolant cools the engine coolant (jacket water). The external coolant goes through heat exchanger (1) when the engine is running. The engine coolant (jacket water) only goes through expansion tank (2) and around the tubes of heat exchanger (1) when the water temperature regulator in the engine is open.
External Coolant Source The external coolant comes in through inlet (30). Auxiliary pump (23) is driven by the timing gears. The location of auxiliary pump (23) is on the left front side of the engine below engine oil cooler (24). Rotation of the impeller pushes the external coolant through inlet line (21) to heat exchanger (1). In heat exchanger (1) the external coolant goes through the tubes and out through outlet line (18) and outlet (26). The engine coolant (jacket water) goes through expansion tank (2) and around the tubes of heat exchanger (1). This cools the engine coolant (jacket water).
Engine Coolant (Jacket Water) Circuit Water pump (22) for this circuit is on the left front side of the engine. It is gear driven by the timing gears. Coolant from expansion tank (2) goes through inlet line (20) to the water pump inlet. The rotation of the impeller in water pump (22) pushes the coolant (jacket water) through the circuit. The coolant flow from water pump (22) is divided. Some of the coolant flow goes through engine oil cooler (24). The remainder of the coolant flow goes through aftercooler inlet line (8) into the core of the aftercooler. The core of the aftercooler is a group of tubes. These tubes are in a position inside aftercooler housing (12). The coolant goes through the tubes. This inlet air for the engine goes around the tubes. This cools the inlet air. The coolant comes out at the rear of the engine and goes through aftercooler outlet line (14) to bonnet (19). In bonnet (19) the coolant flow mixes with the coolant flow from engine oil cooler (24). The coolant flow which comes through engine oil cooler (24) goes through bonnet (19). If the engine has a water cooled turbocharger (11), some of the coolant flow from engine oil cooler (24) goes through turbocharger inlet line (16). The coolant flow goes in at the bottom of water cooled turbocharger (11) and comes out at the top. It goes through outlet line (10) to the top of water cooled manifold (9). It goes through water cooled manifold (9) to the front of the engine. It comes out through outlet line (6) and goes into regulator housing (7). The coolant flow mixes with the rest of the coolant from the engine.
The remainder of coolant flow through bonnet (19) goes into one side of auxiliary oil cooler (25). At the bottom the coolant flow turns and goes up the other side of auxiliary oil cooler (25) and into bonnet (19) again. Bonnet (19) sends this flow into cylinder block (17). Inside cylinder block (17) the coolant goes around the cylinder liners and up through the water directors into cylinder head (13). The water directors send the flow of coolant around the valves and the passages for exhaust gases in cylinder head (13). The coolant goes to the front of cylinder head (13). Here the water temperature regulator controls the direction of the flow. If the coolant temperature is less than normal for engine operation, the water temperature regulator is closed. The only way for the coolant to get out of cylinder head (13) is through internal bypass (shunt) line (15). The coolant from this line goes into water pump (22) which pushes it through the cooling system again. The coolant from internal bypass (shunt) line (15) also works to prevent cavitation (air bubbles in the coolant). When the coolant gets to the correct temperature, the water temperature regulator opens and coolant flow is divided. Some goes through expansion tank (2) and around heat exchanger (1) for cooling. The rest goes through internal bypass (shunt) line (15) to water pump (22). The proportion of the two flows is controlled by the water temperature regulator. NOTE: The water temperature regulator is an important part of the cooling system. It divides the coolant flow between heat exchanger (1) and internal bypass (shunt) line (15), as necessary, to maintain the correct operating temperature. If the regulator is not installed, there is no mechanical control, and most of the coolant will take the path of least resistance through internal bypass (shunt) line (15). This will cause the engine to overheat in hot weather. In cold weather, even the small amount of coolant that goes through heat exchanger (1) is too much, and the engine will not get up to normal operating temperature.
Internal bypass (shunt) line (15) has another function when the cooling system is being filled. It lets the coolant go into cylinder head (13) and cylinder block (17) without going through water pump (22). The coolant flow from the engine goes through outlet line (5) to expansion tank (2) and heat exchanger (1). Heat exchanger (1) is cooled by external coolant sent by auxiliary pump (23) through inlet line (21). The external coolant cools the engine coolant in expansion tank (2) and goes out through the outlet for external coolant source (26). Expansion tank (2) is the reservoir for the cooling system. It is the highest place in the cooling system. It is the place where the volume of the coolant can change because of heating or cooling without causing too much or too little coolant for the cooling system. Expansion tank (2) has a pressure cap (3) to control the pressure in the cooling system for better operation.
Cooling System Components Water Pump The centrifugal-type water pump has two seals. One prevents leakage of water and the other prevents leakage of lubricant.
An opening in the bottom of the pump housing allows any leakage at the water seal or the rear bearing oil seal to escape.
Fan The fan is driven by two V-belts, from a pulley on the crankshaft. Belt tension is adjusted by moving the clamp assembly which includes the fan mounting and pulley.
Coolant For Air Compressor
Coolant Flow In Air Compressor (1) Outlet hose. (2) Air compressor. (3) Inlet hose.
The coolant for the air compressor (2) comes from the cylinder block through hose (3) and into the air compressor. The coolant goes from the air compressor through hose (1) back into the front of the cylinder head.
Basic Block Cylinder Block And Liners A steel spacer plate is used between the cylinder head and the block to eliminate liner counterbore and to provide maximum liner flange support area (the liner flange sits directly on the cylinder block). Engine coolant flows around the liners to cool them. Three O-ring seals at the bottom and a filler band at the top of each cylinder liner form a seal between the liner and the cylinder block.
Pistons, Rings And Connecting Rods The piston has three rings; two compression and one oil ring. All rings are located above the piston pin bore. The two compression rings seat in an iron band which is cast into the piston. Pistons in some engines use compression rings with straight sides. Pistons in other engines use compression rings which are of the KEYSTONE type. KEYSTONE rings have a tapered shape and the movement of the rings in the piston groove (also of tapered shape) results in a constantly changing clearance (scrubbing
action) between the ring and the groove. This action results in a reduction of carbon deposit and possible sticking of rings. The oil ring is a standard (conventional) type and is spring loaded. Holes in the oil ring groove provide for the return of oil to the crankcase. The piston pin bore in the piston is offset (moved away) from the center of the piston 0.76 mm (.030 in). The full floating piston pin is held in the piston by two snap rings which fit into grooves in the piston pin bore. The piston pin end of the connecting rod is tapered to give more bearing surface at the area of highest load. The connecting rod is installed on the piston with the bearing tab slots on the same side as the "V" mark on the piston.
Crankshaft The crankshaft changes the combustion forces in the cylinder into usable rotating torque which powers the machine. There is a gear at the front of the crankshaft that drives the timing gears and the engine oil pump. The connecting rod bearing surfaces get oil for lubrication through passages drilled in the crankshaft. A lip type seal and wear sleeve is used to control oil leakage in the front crankshaft seal. A hydrodynamic grooved seal assembly is used to control rear crankshaft oil leakage. The hydrodynamic grooves in the seal lip move lubrication oil back into the crankcase as the crankshaft turns.
Vibration Damper The force from combustion in the cylinders will cause the crankshaft to twist. This is called torsional vibration. If the vibration is too great, the crankshaft will be damaged. The vibration damper limits torsional vibrations to an acceptable amount to prevent damage to the crankshaft. The viscous damper is made of a weight (1) in a case (3). The small space (2) is filled with a thick fluid. The fluid permits the weight to move in the case to cause a reduction of vibrations of the crankshaft.
